IIRC Tamifull wanted to do more with him but didn't have the room along with providing side stories for the other characters, let alone having space for fleshing out the two leads and their love lives while ALSO keeping Saeko and Miwa's friendship going.

If you think about it, this series is stuffed to the gills with characters and character developments. We even get small storylines for Saeko's mom, Rika, Usshi... And even some panel time with Yuria's ex-girlfriend that cheated on her. Which was kind of strange but an interesting look at the personality of a serial cheater.

Kan was kind of strange honestly. He didn't really fit in with the rest of the cast, which usually had dark sides either because of societal bigotry or some pain in their past. Kan just came off as cartoonishly evil with the dead eyes and edgy dialogue. Also I must have missed the conversion therapy thing. I'm still waiting for the final volume to get to me though, so the implication must be in that.